https://doi.org/10.1140/epjqt/s40507-025-00401-x
Research
Demonstration of strong coupling of a subradiant atom array to a cavity vacuum
1
HUN-REN Wigner RCP, P.O. Box 49, H-1525, Budapest, Hungary
2
Department of Theoretical Physics, University of Szeged, Tisza Lajos körút 84, H-6720, Szeged, Hungary
3
Université Paris-Saclay, CNRS, ENS Paris-Saclay, CentraleSupélec, LuMIn, 91190, Gif-sur-Yvette, France
4
Department of Physics of Complex Systems, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117, Budapest, Hungary
a
nagy.david@wigner.hun-ren.hu
Received:
30
April
2025
Accepted:
28
July
2025
Published online:
5
August
2025
By considering linear scattering of laser-driven cold atoms inside an undriven high-finesse optical resonator, we experimentally demonstrate effects unique to a strongly coupled vacuum field. Arranging the atoms in an incommensurate lattice with respect to the radiation wavelength, the Bragg scattering into the cavity can be suppressed by destructive interference: the atomic array is subradiant to the cavity mode under transverse illumination. We show however, that strong collective coupling leads to a drastic modification of the excitation spectrum, as evidenced by well-resolved vacuum Rabi splitting in the intensity of the fluctuations. Furthermore, we demonstrate a significant polarization rotation in the linear scattering off the subradiant array via Raman scattering induced by the strongly coupled vacuum field.
Key words: Cavity quantum electrodynamics / Cold atoms / Subradiant scattering / Vacuum Rabi splitting
© The Author(s) 2025
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